Telephone system



Aug. 20, 1929. L, J. BOWNE TELEPHONE SYSTEM Filed Nov. 22, 1927 #EGS Arm/wr Patented Aug. 20, 1929.

UNITED STATES PATENT OFFICE.

LANGFOBD J. BOWNE, OF HOWARD BEACH, NEW YORK, ASSIGNOR TO WESTERN ELEC- TRIO COMPANY, INCORPORATED, OF NEXV YORK, N. Y., A CORPORATION OF NEW YORK.

TELEPHONE SYSTEM.

Ap lication filed November 22, 1927. Serial No. 234,951.

This invention relates to telephone sys tems and more particularly to such systems wherein any one of a group of telephone lines may be connected to any one of a number of attendants sets at a subscribers station.

In large oflices wherein several employees or attendants are located in the same room and wherein the business of the oifice is common to each attendant or employee, it is often desirable that telephonic accommodations of such a nature be provided so that any one of the attendants or employees in the room may answer any of the incoming calls without undue inconvenience.

In systems of this general character, it is usual practice to terminate each of a plu rality of telephone lines, incoming to a sub scribers station, in a plurality of key boxes, each of which is located at a particular position at the station and is provided with signaling devices individual to each incoming line. By this arrangement a call, incoming on any one of a group of lines,

disolays a signal at a plurality of positions, and the call may be answered by an attendant or employee at any one of these positions, by the actuation of a key corresponding to the line on which the signals indicate the presence of a call.

It is an object of this invention to improve existing communicating systems of this type and to render such systems more economical to maintain.

This object is attained in accordance with a feature of the invention by the provision of a group of line circuits, each of which terminates at a plurality of positions in a key box, and is provided with signal lamps at each position to indicate to the attendant or employee thereat, the arrival of a call on any one of the lines in a group and the idle or busy condition of such lines.

Another feature of the invention resides in a circuit arrangement whereby, should a call incoming to a particular position remain unanswered, the lighted line lamps are extinguished and audible signals, if employed, silenced a specified time interval after ringing ceases. This feature, prevents undue battery drain and reduced life of the line lamps should a subscriber fail to cut off battery from the equipment when it is unattended.

A further feature of the invention is embodied in a circuit arrangement whereby the line lamps are held lighted over the silent interval in ringing of an interrupted character such as machine ringing on incoming calls.

A still further feature resides in the provision of means for holding the line lamps lighted for an appreciable interval after ringing ceases on manual ring incoming calls.

The features of this invention are attained by the provision of a relay timing circuit which is common to a plurality of line circuits and functions therewith in such a manner as to prevent the release of a signal control relay until a predetermined time period has elapsed since the signaling current has been disassociated from the line circuit.

The invention will be readily understood from the following detailed description made with reference to the accompanying drawing which shows a plurality of line circuits, part in full and part schematic, terminating at a plurality of positions in a key box, and the timing circuit which functions with these line circuits.

Referring in general to the drawing the line circuit L is shown in full, terminating at a subscribers station B in a plurality of key boxes at the attendants or employees positions K and K It is to be understood that the number of line circuits and the p0- sitions at which. these circuits terminate are not limited to the two shown. Each line is provided with a buzzer and each group of lines with a similar signaling device which function jointly with the regular line lamps to indicate the presence of a call on any or on a particular line. A key is provided in the common buzzer circuit, the actuation of which is optional. The relay timing circuit T is common to a plurality of line circuits such as L and L,.

In the following description it will be assumed that the line circuit L has been selected for use in the establishment of a conmotion to the subscribers station B at which each of a plurality of lines, such as L and L terminate in a plurality of multiple keys. The application of ringing current from any suitable source to the tip and ring contacts of jack 11 traverses the windings of ringing relay 14. Relay 14 thereupon operates atfecting a circuit for relay 15 i of relay 17.

which may be traced from grounded battery, resistance 51, winding of, relay 15, normal make-before-break contacts of relay 16, front contact and upper armature of relay 14 to ground by way of the uppermost armature and back contact of relay l7. Relay 15 operates slowly and, by way of its upper armature and front contact, extends the circuit from the front contact and upper armature of relay 14 to battery and ground through the winding of relay 16. Relay 16 operates in this circuit and, in attracting its' uppermost armature, opens the circuit for relay 15 and locks itself in a circuit extendlowermost armature and back contact of relay 1?, winding of relay 18 to ground on the back contact and outer right-hand arinature of relay 28. Relay 18 operates in this circuit causing the operation of the audible signal 20 which is common to the positions at station B if the key 52 in the common buzzer circuit is actuated. At its lowermost armature and front contact relay 16 effects the operation of the audible signal 21 which is individual to the particular line L. At its inner lower armature and front contact relay 16 causes the line lamps 22 and 23 to be lighted. The circuit for these lamps may be traced from grounded battery, lower armature and back contact of relay 15, inner lower armature and front contact of relay 16, conductor 24, through the filaments of all lamps such as 22 and 23 at all key box positions such as K and K, to ground. These lamps appear at'all the attendants or employees key boxes to which the line L is multipled and any subscriber at such a position may answer a call in a manner which will hereinafter appear. lVhen ringing current ceases, relay 14 restores and relay 16 remains locked up under the control of relay 17 and the timing circuit T.

Reverting back to the operation of relay 14 upon the application of ringing current to the line 11, it will be noted that at its lower armature relay 14 connects ground to the timing circuit T whereupon relays 25 and 26 operate in a circuit extending from grounded battery, windings of relays 26 and 25 in series, conductor 27, lower front contact and armature of relay 14 to ground on the uppermost armature and back contact Relay 26 locks in an obvious circuit to ground on the back contact and outer right-hand armature of relay 28. At the end of the ringing period relay 14 in the line circuit restores, opening the circuit for relay 25 which releases slowly. The release of relay 25establishes a circuit from grounded battery, back contact and armature of relay 25, left-hand armature and front contact of relay 26, back contact and outer right-hand armature of relay 29, righthand armature and back contact of relay 30, left-hand armatures and back contacts of relays 31' and 32 through the resistance 34,

winding of relay 33 to ground. Relay 33 operates in this circuit and, in attracting its right-hand armature, short-circuits the resistance element 34. The purpose of this last operation is to permit the maximum amount of current to flow through relay 33 to render this relay slow to release when relay 32 op crates as will be seen presently.

Relay 33 in attracting its left-hand armature causes relay32 to operate a circuit including the resistance element 35. Relay 32 operates, opening at its left-hand armature and back contact the holding circuit for relay 33. Relay '32 locks in a circuit eX- tending from grounded battery, back contact and armature of relay '25, left-hand armature and front contact of relay 26, back contact and outer right-hand armature of relay 29, right-hand armature and back contact of relay 30, left-hand armature and back contact of relay 31, left-hand armature and front contact and winding of relay 32 to ground. At its left-hand armature relay 32 short-circuits the resistance element 35 to render itself slow releasing when its locking circuit is open. At its right-hand armature relay 32 prepares an operating circuit for relay 31 by way of re sistance element 36 which circuit is completed when relay 33 restores as will presently appear.

Relay 33 releases as a consequence of the operation of relay 32 and completes the aforementioned operating circuit for relay 31 which was prepared by the operationof relay 32. Relay 31 thereupon operates, opens the circuit to the winding of relay 32, and locks up in a circuit extending from grounded battery, back contact and armature of relay 25, left-hand armature and front contact of relay 26, back contacts and outer right-hand armature of relay 29, right-hand armature and back contact of relay 30, left-hand itl'lfifitlllfifllld front contact and winding of relay 31 to ground. Relay 31 in operating short-circuits the resistance element 36 for a purpose similar to that described in connection with the short-circuiting of resistances 34 and 35. At its lefthand armature relay 31 opens the locking circuit for relay 32 which releases slowly and causes relay 30 to operate in a circuit 8X- tending from grounded battery, right-hand armatures and back contacts of relays 33 and 32, right-hand armature and front contact of relay 31, resistance element 38, winding of relay 30 to ground. Relay 30 upon operating, opens the locking circuit for relay 31, short-circuits the resistance element 38 and locks in a manner similar to that described in connection with relays 31, 32 and 33. When relay 31 restores it closes a circuit extending from grounded battery, left-hand armature and back contact of relay 33, right-hand armature and back contact of relay 32, right-hand armature and back contact of relay 31, front contact and left-hand armature of relay 30, left-hand armature and back contact of relay 28, winding of relay 29, right-hand winding of relay 28 to ground. Relay 29 is provided with a high resistance winding and relay 28, being marginal, does not operate at this time but relay 29 does operate and at its outer right-hand armature opens the circuit for relay 30 which thereupon restores slowly. At its left-hand armature and front contact relay 29 shunts the outer righthand contacts of relay 28 to prevent the release of the signal control relay 16 at this time and at its innerright-hand armature and front contact connects battery to the lef -hand winding of relay 28. It will be noted that the left-hand winding of relay 28 has now two opposing batteries connected to it, one by way of the left-hand armature and back contact of relay 33, righthand armatures and back contacts of relays 32 and 31, front contact and left-hand armature of relay 30, left-hand armature and back contact of relay 28, and the other by way of the back contact and armature of relay 25, left-hand armature and front contact of relay 26, and the front contact and inner right-hand armature of relay 29. \Vhen relay 30 is finally released, this shortcircuit is removed and relay 28 operates in a circuit extending from grounded battery, back contact and armature of relay 25, lefthand armature and front contact of rela 26,- front contact and inner right-hand armature of relay 29, left-hand winding'of relay 28, winding of relay 29 to ground, through the right-hand winding of relay 28.

Relays and 28 are now operated in series. Relay 28 in operating opens, at its outer right-hand armature, the locking ground for relay 26 but this relay is now held to ground on the front contact and left-hand armature of relay 29. The substitution of this ground for the ground on the outer right-hand armature of relay 28 also serves the purpose of maintaining the signal control relay 16 operated. At its inner right-hand armature relay 28 effects a circuit extending from grounded battery. back contact and armature of relay 25, left-hand armature and front cont-act of relay 26, front contact and inner right-hand armature of relay 28, right-hand armature and back contact of relay 30, left-hand armatures and back contacts of relays 31 and 32, resistance element 34 to ground through the winding of relay 33. Relay 33 is the first of the timing relays and again functions in this circuit to repeat the cycle of operations just described. During this second cycle of operations relays 28 and 29 remain operated.

\Vhen relay 30 operates during this second cycle it short-circuits the winding of relay 29 and the left-hand winding of relay 28 inasmuch as opposing batteries are connected to these windings, one by way of the back contact and armature of relay 25, left-hand armature and front contact of relay 26, front contact and inner right-hand armature of relay 29, left-hand winding of relay 28, winding of relay 29 to the front left-hand contact of relay 28 and the other by Way of the left hand armature and back contact of relay 33, right-hand armature and back contacts of relays 32 and 31, front contact and lefthand armature of relay 30, left-hand armature of relay 28 to the same front contact mentioned in the previously traced circuit. Relay 28, however, is held operated by way of its right-hand winding. Relay 29 restores, removing ground from conductor 39, opening the locking .path for relay 26 which thereupon releases. The removal of ground from conductor 39 causes the release of relay 16 of line circuit L, and the corresponding relays of other line circuits which may have been operated which silences the buzzers 20 and 21 and extinguishes the line lamps 22 and 23 and all other line lamps associated with the line.

Relay 26, in restoring, opens the locking path for relay 30, whereupon relay 28 releases restoring the timing circuit to normal condition.

In the event that all the positions such as K and K are not unattended the call just y described would have been answered in the following manner before the timing circuit had functioned to extinguish the line lamps and silence the audible signals.

Assuming that the call is answered by the attendant or employee at position K the key 40 is actuated from the right, through the middle or talking position, whereupon the telephone set at S, is connected in bridge .Of the tip and ring of the line circuit L and in series with relay 41. Relay 41 opcrates from battery associated with the link circuit which would normally be connected to the line circuit L, when the receiver at station K is removed from the switchhook. This operation is well known and needs no further explanation. As a consequence of the operation of relay 41, relays 42 and 17 operate in obvious circuits.

Relay 17 causes the busy lamps 55 and 43 to be lighted, prepares a circuit for the holding relay 44, interrupts the functioning of the timing circuit T and opens the locking circuit for relay 1.6 whereupon this relay restores extinguishing the lighted line lamps and silencing the audible signals.

If the attendant or employee at position K, has occasion to hold the connection she may do so by actuating the key 40 to the left, or holding position. This operation causes relay 44 to be bridged across the tip and ring conductors of the line by way of the upper inner armature and front contact of relay 1'? and the lower alternate tip contacts of key 40 in the holding position. Relay 44 has a low resistance winding and operates from battery in the link circuit associated with the line L, and at its upper armature and front contact closes a locking circuit for itself before slow releasing relay 17 releases as a consequence of the actuation of the key 40 to the holding position. At its lower armature and front contact relay 44 maintains the busy lamps 42 and 41 lighted in an obvious circuit.

The holding circuit may be released by either restoring the key 40 to normal or returning it to the talking position. In either of these positions the lower tip contacts of key 40 in the holding position are open, causing relay 44 to restore. With the telephone set bridged across the line, relay 41 may not operate at this instant due to the shunt in cluding relay 44, particularly if the line is connected to a very long central office loop. But as soon as relay 44 restores, relay 41, and consequently relays 42 and 17, will reoperate to relight the busy lamps 42 -and 43.

It will also be noted that in the case of a central oliice automatic connection, the connection of the telephone set in bridge of the line before the holding bridge is removed serves to prevent the release of the equipment at the central ofiice.

Returning now to the timing circuit T it will be noted that during the operation of the relay chain in this circuit a second ring may be received by a relay such as 14 associated with another line such as L Under this condition relay 25 will reoperate in series with relay 26 and in parallel with resistance 50, removing at its armature and back contact battery from the timing relays 29 to 33 inclusive, restoring whatever or these relays are operated. lVhen the ring ing ceases relay 25 restores and starts the timing circuit functioning again.

From the foregoing description it is evident that the initiation of a ringing signal in the system disclosed causes the maintenance of the visual and audible signals for a predetermined period of time after the application of signaling current to the line and that in the event there is no attendant or employee available to answerthe incoming call the visual signals will be extinguished and the audible signals silenced.

It is also quite apparent that in the event line circuit L is associated with automatic equipment with which machine ringing current is employed to actuate ringing relay 14, the relay timing circuit will function in a manner similar to that hereinbefore described and would maintain the signal control relay 16 operated between inter uptions of the ringing current to effect the steady glow of the line lamps 22 and 23 and the steady operation of the audible signals such as 20 and 21.

It is to be understood that callsmay originate at station E either manually or by dial but as this phase of the circuit does not enter into the invention it is believed unnecessary to enter into any detailed description of an outgoing call. However it is not amiss to mention that in the case of a dial connection relay 41 follows the dial pulses but owing to the slow characteristics of relays 42 and 17 remains operated causing relay 44 to hold up and maintain the busy signals 42 and 43 operated.

What is claimed is:

1. In a telephone system, a subscribers station, a line terminating thereat at a plurality of attendants positions, signals at said positions, arelay actuated upon the application of signaling current to said line, means controlled thereby for operating said signals, and means for automatically disabling said signals a predetermined period of time after the release of said relay.

2. In a telephone system, a subscribers station, a line terminating thereat at a plurali y of attendants positions, signals at said positions, a relay actuated upon the application of signaling current to said line, means con trolled thereby for operating said signals, and a relay chain for disabling said signals a predetermined periodof time after the release of said relay.

3. In a telephone system, a subscribers station, a line terminating thereat in a key at a plurality of attendants positions, signals at said positions, a relay actuated upon the application of signaling current to said line, a signal control relay operated in response to the actuation of said first relay to effect the actuation of said signals and means formaintaining said signals actuated a predes termined period of time after said first relay restores, said means being rendered ineffective upon the actuation of a key at said station and the response of a subscriber thereat.

4. In a telephone system, a subscribers station, a line terminating thereat at a plurality of attendants positions, signals at said positions, a relay responsive to current incoming over said line, a signal control relay respon- Ell sive to the operation of said first relay to effect the actuation of said si nals, a locking circuit for said signal control relay, and a relay timing circuit adapted to open said locking circuit a predetermined period of time after the release of said first relay to disable said signals.

5. In a telephone system, a line circuit, a signal therefor, a relay associated therewith responsive to signaling current incoming over said line to efiect the actuation of said signal, cyclically operating means adapted to start a new cycle of operation upon each operation of said relay to maintain said signal actuated between successive operations of said relay.

6. In a telephone system, a subscribers station, a line terminating thereat at a plurality of attendants positions, signals at said positions, means responsive to the application of signaling current to said line for actuating said signals, and means operating cyclically for maintaining said signals actuated for a certain period of time should said station be unattended.

7. In a telephone system a subscribers staion, a line terminating thereat at a plurality of attendants positions, signals at said positions, means responsive to the application 01 signaling current to said line for actuating said signals, and a relay chain operating cyclically to maintain said si nals actuated for a certain period of time should said station be unattended.

8. In a telephone system, a subscribers station, a line terminating thereat, a signal for said line, means responsive to the application of signaling current to said line for actuating said signal, and means operating cyclically for interrupting the actuating circuit for said signal a predetermined period of time after said signal was actuated.

9. In a telephone system, a line circuit, a signal therefor, a relay in bridge of said line circuit responsive to signaling current incoming over said line, a signal control relay responsive to the actuation of said first relay to effect the actuation of said signal, and a relay timing circuit adapted to operate cyclically and start a new cycle upon each operation of said first'relay to maintain said signal control relay actuated between successive operations of said. first relay.

. 10. In a telephone system, a line circuit, a signal therefor, a relay responsive to current incoming over said line for actuating said signal, and a chain of relays adapted to operate in a certain sequence upon the first operation of said relay to maintain said signal actuated after the release of said relay and to interrupt and restart the sequence of operation for each successive operation of said first relay.

11. In a telephone system, a line terminating at a plurality of attendants positions, signals at said position, means responsive to signaling current over said line for actuating said signals, and cyclically operating means adapted to disable said signals during a cer tain cycle of its operation whereby said signals are disabled a certain time interval after the release of said first mentioned means.

In witness whereof, I hereunto subscribe my name this 16th day of November, A. D.

LANGFORD J. BOWNE. 

